Comments on “Robust Stability and Stabilization of Fractional-Order Interval Systems With the Fractional Order <inline-formula> <tex-math notation="TeX">$\alpha$</tex-math></inline-formula>: The <inline-formula> <tex-math notation="TeX">$0<\alpha<1$</tex-math></inline-formula> Case”

Abstract

This note considers the work entitled “Robust Stability and Stabilization of Fractional-Order Interval Systems with the Fractional Order <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$\alpha$</tex-math></inline-formula> : The <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$0&lt;\alpha&lt;1$</tex-math></inline-formula> Case” by Lu and Chen, where the authors meant to provide sufficient and necessary conditions for stability of fractional-order linear-time-invariant interval systems. As this note proves, conditions are only sufficient, since necessity relies unsuitably on the certain case. An example is provided.